What's Hot: Slim and light, easy to use, supports both charge and sync.

What's Not: Takes a few hours to charge up via computer.

Reviewed by Tong Zhang

As more smartphones shut their backdoors to user replaceable batteries, smartphone users on the go often need auxiliary power solutions. PowerSkin provides a combination of power on the go and a protective case in one. They offer battery cases for Android devices such as the HTC One X (not user replaceable battery), BlackBerry devices, Windows Phones and iPhone models. The new PowerSkin for iPhone 4S and iPhone 4 comes with a 1500mAh built-in battery and a soft touch case. The back of the PowerSkin case comes in either Glossy Black or Matte Titanium.

Design

The PowerSkin for iPhone 4S/4 is a silicone case with a hard battery pack built-in on the back. The battery pack only takes about 3/4 of space, but it provides very good protection to the back of your iPhone 4 or iPhone 4S against scratches. The bottom of the case has a built-in dock connector and the entire bottom edge is rigid to provide shock protection for the phone and the 30-pin connector port. The top of the case and side covers are flexible silicone which makes it easier to put the case on and take it off. Be sure to slide the phone into the dock connector first then wrap the case around the rest of the iPhone 4S.

The interior of the case also has soft surface even though the battery portion is not as soft as the silicone part, but it won't scratch up or leave marks on your iPhone 4S when you put the case on. The front edges of the PowerSkin wraps around the iPhone 4S and covers the edges of the front bezel with silicone material, so that when you put the phone face down the case touches the surface not the display. The case is reasonably slim measuring at 0.65" and weighs 2.8 ounces.

Features

The PowerSkin for iPhone 4/4S case is a functional case while giving you extra power on the go. The case has cutouts for the rear camera and flash, side silence button and the top audio out jack and mic hole. The cutout for the silence button fits both Verizon and AT&T iPhone 4 models. As the battery case needs the 30-pin connector port to connect, you can't use it for docking but the case has a micro USB port that allows you to sync and charge while the phone is in the case. The PowerSkin for iPhone 4/4S comes with a USB to micro USB cable and you can charge the case and the phone using a computer or an AC adapter.

Battery

The PowerSkin for iPhone 4/4S has a built-in 1500mAh battery and adds about 4-5 hours of talk time on 3G. The PowerSkin can dump a full charge from the battery pack to the phone within 2 hours, and the most convenient thing is that you can keep using your phone to make phone calls, watch videos, talk on Facetime while it's being charged. The battery has safety features such as short circuit protection and temperature protection and it never gets hot. The PowerSkin battery case has a power button on the bottom left corner that you can press to check on the power level indicated by the four LED lights on the back of the case, and you can also turn the battery pack completely off by pressing and holding the button. The battery will turn off automatically when your iPhone 4S is fully charged.

The PowerSkin for iPhone 4/4S takes a few hours to fully charge via computer or AC outlet. When you plug in the power with your iPhone 4S connected in the case, your iPhone 4S will get charged first, then the case. The LED lights on the back also indicate charging level, and when all four LED lights stay solid, the battery is fully charged.

Conclusion

When you need extra power on the go and case protection, the PowerSkin for iPhone 4/4S can provide both. The battery case is slim and light. It's easy to use and very functional. The extra power is great for adding some extra juice at the end of the day or the last leg of your trip, and you can use your phone easily while it's charging. The battery case supports power through and data pass through, and it has surge and short circuit protection.